br>Good evening! I finished my TM3030 it turns on, the switch works, far so good. I started to calibrate and I adjust the PSU until 5,333 V, I leave 15min, I recheck and it has not changed, still at 5,333 V. Then I go to V / Oct. and That is where it gets stuck at the beginning just as I was hearing a small click-bass, so I turned the trimmer for a long time way, and then my chromatic tuner displayed the symbol "b" and then I heard a small sound like the sound of the VCF and since I'm turning the trimmer I always have the same sound and my chromatic tuner always displays the symbol "b" and he told me that the note is too low. I don't know what to do, it's two hours it lasts, could someone help me please? I'm desperate, this is the 1st time I caliber a synthesizer and there may be a component that prevents the proper functioning ? Yet everything looked ok when I checked with my multimeter but I could check that the resistors and diodes, capacitors, but not because my multimeter does not have this function.

Thanks in advance for answers

Bests, damien br> br>

br>Synthbuilder

br>Ignoring any of the other calibrations at the moment: Can you actually play notes and does it sound like a TB303? If not then they may be a problem with the build. The calibration routines are not going to make a non working TM3030 start to work.

However, if you can play notes and it all sounds fine except for being horribly out of tune, then you probably have built it right and you 'just' need to tune it.

Adjusting the scaling (V/OCT) is tricky - although once you get the hang of it, it can be done very quickly.

Tony br> br>

br>analog therapy

br>Hi ! in fact I do not obtain really note, I just hear the sound of the VCF with white noise, but no, it was not the sound of a TB303, and I have low volume, which is strange it is that all potentiometers work (except accent but I could not yet launched sequence I think it is normal), the LEDs operate as it receives and SLIDE GATE. trimmer PSU work well too, it displays 5.333V and it remains to this position. I noticed that when I press the WAVE switch barely when the TM3030 is connect to my chromatic tuner, my tuner display changes to show me different notes but at the audio is always same. br> br>

br>studyman

br>hello, i've the same problem here ! br> br>

br>Synthbuilder

br>Many types of fault in the analogue signal path can produce this sort of problem and, unfortunately, that's a lot of components to check through. So if the VCO is not oscillating, or the filter (circuitry around U9) not passing audio, you will hear just clicks. The VCA (U15/U14) is probably working so this bit is the last bit to check, but even a fault in the VCA can cause the problem of just clicks.

With a 'scope it is possible find where the signal is being lost. Without a 'scope it is very difficult indeed. So the first thing you need to ascertain is that the power supplies for the analogue sections are working.

With a voltmeter you need to ensure that the 5V3 pad is reading in the region of 5.3V The ADJ trimmer should be used to set that to exactly 5.33V. If you cannot do this then the fault is in the power supply section (around U10).

Pin 7 of U13 should be around 12V. If not then this also indicates a problem with the power supply section. Look for wrong components near U10. It may be worth replacing U10.

If all is well with the above measurements then what are the voltages on pin 2, pin 12, pin 13 and pin 14 of U6? This is the part of the circuitry that controls the VCO pitch. 13 and 14 should be 5.33V and 12 should be 4.6V or so. Pin 2 will vary according to the note you play but it should be around 5.3V.